Easy ownCloudAs Frank pointed out in his blog on the future of PHP, ownCloud has ease of use as an explicit and very important goal. And while the technological choices made aren't always so exciting and bleeding edge, they do result in ownCloud being very easy to deploy on a very wide range of devices. Plenty of tutorials exist showing it running on everything from Rasberry Pi devices to big iron at organizations like CERN, where physicists looking for the origins of the universe are routing hundreds of terrabytes of data through their CernBOX build on ownCloud, sharing and collaborating on the data analysis.
LimitationsUnfortunately, there are limitations outside of what ownCloud can directly control.
In the database area, SQLite is default because it requires no manual setup whatsoever. But performance suffers when an installation has more than a trivial amount of data. When sharing with more than 15 users or indexing your mp3 connection, SQLite usage leads to frequent time-outs and other issues!
Another, more serious issue, is the architecture of the current internet. Most users are set up at home behind a firewall provided by their internet router. While this provides some additional security, it is mainly because the limited number of unique addresses available in the still widely-used 'IPv4' protocol. It simply is impossible to assign a unique address to each device connected to your internet at home. But this means your server will not be reachable when you're not home, unless you adjust some settings on your router. While we can configure some routers automatically, most we can't and as every router is different, an easy 'generic' how-to can't be provided either.
A third issue is that an ideal ownCloud platform would be small and cheap devices like the Raspberry Pi, but these are almost all based on 32bit CPU's. Due to technical limitations in the platform ownCloud builds on, this means you won't be able to have it handle files bigger than about 4 gigabyte! That is a big limitation if you'd like to store your virtual machine or Blue Ray collection on your ownCloud.
The fourth issue I see is security. While not the biggest problem of the three, setting up a server to be secure, including a decent SSL certificate, is not easy. I personally couldn't figure it out and while I'm new to server things, I am not a technology hater by any means. My parents wouldn't ever …